Purpose: We aimed to identify changes in surgical indications in patients with ulcerative colitis (UC) in the biologics era in a single tertiary center. Methods: In this retrospective observational study, 108 patients with UC who underwent abdominal surgery for UC at Seoul National University Hospital from 2000 to 2021 were included. We compared the total number of patients undergoing UC before and after the introduction of biologic therapy. Results: Of the 108 patients with UC (male, 59 and female, 49; mean age, 46.8 years), 30 (27.8%) underwent surgery for neoplasms and 78 (72.2%) for medical intractability without neoplasms. The duration between diagnosis and surgery varied significantly (126.00 months vs. 60.50 months, P = 0.001). A significant difference was also noted in the surgical indications according to time (P = 0.02). Between 2000 and 2010, 12 patients (19.4%) underwent surgery for UC with neoplasms and 50 (80.6%) for UC without neoplasms, while between 2011 and 2021, 18 (39.1%) and 28 patients (60.9%) underwent surgery for UC with and without neoplasms, respectively. Conclusion Since 2011, when biological agents were covered by insurance in South Korea, there has been a relative increase in the incidence of surgical indications for neoplasia cases. Focusing on closely monitoring individuals with longterm UC for neoplasms is necessary.

Purpose: We aimed to identify changes in surgical indications in patients with ulcerative colitis (UC) in the biologics era in a single tertiary center. Methods: In this retrospective observational study, 108 patients with UC who underwent abdominal surgery for UC at Seoul National University Hospital from 2000 to 2021 were included. We compared the total number of patients undergoing UC before and after the introduction of biologic therapy. Results: Of the 108 patients with UC (male, 59 and female, 49; mean age, 46.8 years), 30 (27.8%) underwent surgery for neoplasms and 78 (72.2%) for medical intractability without neoplasms. The duration between diagnosis and surgery varied significantly (126.00 months vs. 60.50 months, P = 0.001). A significant difference was also noted in the surgical indications according to time (P = 0.02). Between 2000 and 2010, 12 patients (19.4%) underwent surgery for UC with neoplasms and 50 (80.6%) for UC without neoplasms, while between 2011 and 2021, 18 (39.1%) and 28 patients (60.9%) underwent surgery for UC with and without neoplasms, respectively. Conclusion Since 2011, when biological agents were covered by insurance in South Korea, there has been a relative increase in the incidence of surgical indications for neoplasia cases. Focusing on closely monitoring individuals with longterm UC for neoplasms is necessary.

Purpose: We aimed to identify changes in surgical indications in patients with ulcerative colitis (UC) in the biologics era in a single tertiary center. Methods: In this retrospective observational study, 108 patients with UC who underwent abdominal surgery for UC at Seoul National University Hospital from 2000 to 2021 were included. We compared the total number of patients undergoing UC before and after the introduction of biologic therapy. Results: Of the 108 patients with UC (male, 59 and female, 49; mean age, 46.8 years), 30 (27.8%) underwent surgery for neoplasms and 78 (72.2%) for medical intractability without neoplasms. The duration between diagnosis and surgery varied significantly (126.00 months vs. 60.50 months, P = 0.001). A significant difference was also noted in the surgical indications according to time (P = 0.02). Between 2000 and 2010, 12 patients (19.4%) underwent surgery for UC with neoplasms and 50 (80.6%) for UC without neoplasms, while between 2011 and 2021, 18 (39.1%) and 28 patients (60.9%) underwent surgery for UC with and without neoplasms, respectively. Conclusion Since 2011, when biological agents were covered by insurance in South Korea, there has been a relative increase in the incidence of surgical indications for neoplasia cases. Focusing on closely monitoring individuals with longterm UC for neoplasms is necessary.

Background: Recent guidelines about preventing surgical site infections (SSIs) recommend against the administration of prophylactic antibiotics after surgery. However, many colorectal surgeons still prefer prolonged use of prophylactic antibiotics. While minimally invasive surgery (MIS) has become the standard for colorectal cancer surgery, there were few studies about proper dose of prophylactic antibiotics in minimally invasive colorectal surgery. Methods: This is a retrospective study. All patients underwent elective colorectal cancer surgery using MIS. Intravenous cefotetan was administered as a prophylactic antibiotic.Two groups were classified according to the dose of prophylactic antibiotics: a group using a single dose preoperatively (single-dose group) and a group using a preoperative single dose plus additional doses within 24 hours after surgery (multiple-dose group). The SSI rates between the two groups were compared before and after propensity score matching (PSM).Risk factors of SSIs were assessed using univariate and multivariable analysis. Results: There were 902 patients in the single-dose group and 330 patients in the multipledose group. After PSM, 320 patients were included in each group. There were no differences in baseline characteristics and surgical outcomes except the length of hospital stay. SSI rates were not different between the two groups before and after PSM (before 2.0% vs. 2.1%, P = 0.890; after 0.9% vs. 1.9%, P = 0.505). In multivariable analysis, American Society of Anesthesiologists class 3, rectal surgery, intraoperative transfusion, and larger tumor size were identified as independent factors associated with SSI incidence. Conclusion A single preoperative dose of prophylactic antibiotics may be sufficient to prevent SSIs in elective MIS for colorectal cancer.

Background: Recent guidelines about preventing surgical site infections (SSIs) recommend against the administration of prophylactic antibiotics after surgery. However, many colorectal surgeons still prefer prolonged use of prophylactic antibiotics. While minimally invasive surgery (MIS) has become the standard for colorectal cancer surgery, there were few studies about proper dose of prophylactic antibiotics in minimally invasive colorectal surgery. Methods: This is a retrospective study. All patients underwent elective colorectal cancer surgery using MIS. Intravenous cefotetan was administered as a prophylactic antibiotic.Two groups were classified according to the dose of prophylactic antibiotics: a group using a single dose preoperatively (single-dose group) and a group using a preoperative single dose plus additional doses within 24 hours after surgery (multiple-dose group). The SSI rates between the two groups were compared before and after propensity score matching (PSM).Risk factors of SSIs were assessed using univariate and multivariable analysis. Results: There were 902 patients in the single-dose group and 330 patients in the multipledose group. After PSM, 320 patients were included in each group. There were no differences in baseline characteristics and surgical outcomes except the length of hospital stay. SSI rates were not different between the two groups before and after PSM (before 2.0% vs. 2.1%, P = 0.890; after 0.9% vs. 1.9%, P = 0.505). In multivariable analysis, American Society of Anesthesiologists class 3, rectal surgery, intraoperative transfusion, and larger tumor size were identified as independent factors associated with SSI incidence. Conclusion A single preoperative dose of prophylactic antibiotics may be sufficient to prevent SSIs in elective MIS for colorectal cancer.

Background: Recent guidelines about preventing surgical site infections (SSIs) recommend against the administration of prophylactic antibiotics after surgery. However, many colorectal surgeons still prefer prolonged use of prophylactic antibiotics. While minimally invasive surgery (MIS) has become the standard for colorectal cancer surgery, there were few studies about proper dose of prophylactic antibiotics in minimally invasive colorectal surgery. Methods: This is a retrospective study. All patients underwent elective colorectal cancer surgery using MIS. Intravenous cefotetan was administered as a prophylactic antibiotic.Two groups were classified according to the dose of prophylactic antibiotics: a group using a single dose preoperatively (single-dose group) and a group using a preoperative single dose plus additional doses within 24 hours after surgery (multiple-dose group). The SSI rates between the two groups were compared before and after propensity score matching (PSM).Risk factors of SSIs were assessed using univariate and multivariable analysis. Results: There were 902 patients in the single-dose group and 330 patients in the multipledose group. After PSM, 320 patients were included in each group. There were no differences in baseline characteristics and surgical outcomes except the length of hospital stay. SSI rates were not different between the two groups before and after PSM (before 2.0% vs. 2.1%, P = 0.890; after 0.9% vs. 1.9%, P = 0.505). In multivariable analysis, American Society of Anesthesiologists class 3, rectal surgery, intraoperative transfusion, and larger tumor size were identified as independent factors associated with SSI incidence. Conclusion A single preoperative dose of prophylactic antibiotics may be sufficient to prevent SSIs in elective MIS for colorectal cancer.

Background: Recent guidelines about preventing surgical site infections (SSIs) recommend against the administration of prophylactic antibiotics after surgery. However, many colorectal surgeons still prefer prolonged use of prophylactic antibiotics. While minimally invasive surgery (MIS) has become the standard for colorectal cancer surgery, there were few studies about proper dose of prophylactic antibiotics in minimally invasive colorectal surgery. Methods: This is a retrospective study. All patients underwent elective colorectal cancer surgery using MIS. Intravenous cefotetan was administered as a prophylactic antibiotic.Two groups were classified according to the dose of prophylactic antibiotics: a group using a single dose preoperatively (single-dose group) and a group using a preoperative single dose plus additional doses within 24 hours after surgery (multiple-dose group). The SSI rates between the two groups were compared before and after propensity score matching (PSM).Risk factors of SSIs were assessed using univariate and multivariable analysis. Results: There were 902 patients in the single-dose group and 330 patients in the multipledose group. After PSM, 320 patients were included in each group. There were no differences in baseline characteristics and surgical outcomes except the length of hospital stay. SSI rates were not different between the two groups before and after PSM (before 2.0% vs. 2.1%, P = 0.890; after 0.9% vs. 1.9%, P = 0.505). In multivariable analysis, American Society of Anesthesiologists class 3, rectal surgery, intraoperative transfusion, and larger tumor size were identified as independent factors associated with SSI incidence. Conclusion A single preoperative dose of prophylactic antibiotics may be sufficient to prevent SSIs in elective MIS for colorectal cancer.

Purpose: Globally, chronic kidney disease (CKD) is common and has been associated with an increased risk of colorectal cancer (CRC). There is a dearth of literature on the real-world morbidity and mortality associated with CKD comorbid with CRC. This study was performed to evaluate real-world survival outcomes of colorectal malignancy in Korean CKD patients. Methods: The National Health Insurance Service of Korea provided data on patients who underwent surgical resection among patients diagnosed with CRC from 2002 to 2019. Results: A total of 219,550 patients were included: 6,181 patients with underlying CKD and 213,369 patients without it.Each morbidity was significantly higher in the CKD-CRC group, and the postoperative mortality rates for the 30-day (3.11% vs. 1.78%, P < 0.001), 60-day (5.95% vs. 3.83%, P < 0.001), and 90-day mortality rate (8.12% vs. 5.32%, P < 0.001) were significantly higher in the CKD group. The median survival time (MST, year) was significantly lower in the CKD-CRC group (5.63; interquartile range [IQR], 5.26–5.91) than in the non-CKD-CRC group (8.71; IQR, 8.37–8.93). MST was significantly lower among CKD patients who received chemotherapy after adjustment by multivariate analysis (adjusted hazard ratio [HR], 1.43; 95% confidence interval [CI], 1.37–1.49; P < 0.001]). Subgroup analysis showed that in the CKD-CRC group, MST was lower in patients who received dialysis than in those who did not, even after multivariate analysis (adjusted HR, 2.38;95% CI, 2.20–2.58; P < 0.001). Conclusion Prevention of CKD-to-end-stage renal disease progression should be adopted as a strategy to increase postoperative survival, along with active surveillance and cancer treatment.

Purpose: Circulating tumor DNA (ctDNA) is emerging as a valuable non-invasive tool to identify tumor heterogeneity and tumor burden. This study investigated ctDNA dynamics in metastatic colorectal cancer patients treated with regorafenib. Materials and Methods: In this prospective biomarker study, plasma cell-free DNA (cfDNA) samples obtained at baseline, at the first response evaluation after 2 cycles of treatment, and at the time of progressive disease were sequenced using a targeted next-generation sequencing platform which included 106 genes. Results: A total of 285 blood samples from 110 patients were analyzed. Higher baseline cfDNA concentration was associated with worse progression-free survival (PFS) and overall survival (OS). After 2 cycles of treatment, variant allele frequency (VAF) in the majority of ctDNA mutations decreased with a mean relative change of –31.6%. Decreases in the VAF of TP53, APC, TCF7L2, and ROS1 after 2 cycles of regorafenib were associated with longer PFS. We used the sum of VAF at each time point as a surrogate for the overall ctDNA burden. A reduction in sum (VAF) of ≥ 50% after 2 cycles was associated with longer PFS (6.1 vs. 2.7 months, p=0.002), OS (11.3 vs. 5.9 months, p=0.001), and higher disease control rate (86.3% vs. 51.1%, p < 0.001). VAF of the majority of the ctDNA mutations increased at the time of disease progression, and VAF of BRAF increased markedly. Conclusion Reduction in ctDNA burden as estimated by sum (VAF) could be used to predict treatment outcome of regorafenib.

Ulcerative colitis (UC), a relapsing-remitting chronic inflammatory bowel disease (IBD), has a variable natural course but potentially severe disease course. Since the development of anti-tumor necrosis factor (TNF) agents has changed the natural disease course of moderate-to-severe UC, therapeutic options for patients who failed conventional treatments are expanding rapidly. IBD clinical trials have demonstrated the potential efficacy and safety of novel biologics such as anti-integrin α4β7 and anti-interleukin-12/23 monoclonal antibodies and small molecules such as a Janus kinase inhibitor. Anti-TNF biosimilars also have been approved and are widely used in IBD patients. Wise drug choices should be made considering evidence-based efficacy and safety. However, the best position of these drugs remains several questions, with limited data from direct comparative trials. In addition, there are still concerns to be elucidated on the effect of therapeutic drug monitoring and combination therapy with immunomodulators. The appropriate treatment regimens in acute severe UC and the risk of perioperative use of biologics are unclear. As novel biologics and small molecules have been approved in Korea, we present the Korean guidelines for medical management of adult outpatients with moderate-to-severe UC and adult hospitalized patients with acute severe UC, focusing on biologics and small molecules.